This invention relates to a continuous, automatic method of manufacturing, by a wet method, glass fiber-reinforced cement plates (which will be called GRC plates hereinafter) that are utilized as building materials like wall materials, fireproofing covering materials, sound insulating materials and so forth, and are advantageous because they are light weight and possess superior mechanical strength.
Conventional GRC plates have generally been manufactured by means of a spray up method comprising the steps of preparing a normal Portland cement mortar, cutting glass fiber by a cutter in suitable lengths so as to prepare chopped strand fibers, spraying said mortar and chopped strand fibers simultaneously in a flask so as to provide a suitable thickness, subjecting the same to one day's natural curing, and thereafter removing it from the flask.
This spray up method does not need special manufacturing techniques and equipment, but it is defective in that the productivity of the spray up method, which is operated by the batch method, cannot be increased and consequently it involves unavoidable difficulties in providing cheap products.
Furthermore, conventional GRC plates have been manufactured in accordance with another method comprising the steps of spraying a cement-water type slurry together with chopped strands of glass fibers onto a conveyor to thereby form a layer of a mixture of both materials, and subjecting said layer to low pressure dehydration for hardening. This method is defective in that a water permeable mat and a dehydrating device are required in this case. Moreover, since it is difficult under existing circumstances to carry out the dehydration effectively, the products lack uniformity in quality. Moreover, since a long period of time is required for curing, the molding cycle is prolonged with reduced productivity, whereby it becomes extremely difficult, by this method, to provide cheap products.